Process for treating the surface of bronze, brass, and like metals



Patented May 19, 19 25.

UNITED STATES- 1,538,792 PATENT OFFICE.

RICHARD WILLIAM HENRY FOX, OF PALMERS GREEN, ENGLAND.

PROCESS FOR- TREATING THE SURFACE OF BRONZE, BRASS, AND LIKE METALS.

N'o Drawing.

To .all wkom it may concern:

Be 1t known that I, 'Ricrrnnn VVTLLIAM HENRY Fox, a subject of the King of Great Britain, residing at. Palmers Green, in the coating which is capable of withstanding the action of the weather, including the corrosive action of the acid-laden atmosphere of towns, so that it is only necessary to wash the treated surfaces with water from time to time in order to removeiany dust, etc. that may have attached itself thereto. An other object of my invention is to enable such treatment to be carried out in the open air and at ordinary atmospheric temperatures, thus permitting external bronze and brass work, such as statuary, railings, window frames, doors, facias, panels, shop fronts, verandas, etc. to be treated in situ.

According to my invention, the corroded surface is treated preferably in a dry condition directly with metal brushes or scrap\ s so as to remove the unsightly products of corrosion and to expose the patinalike surface covering the pure or una'cted upon metal, whereupon the said patinalike surface is covered with a light coating of a coloring material known as bronze powder or composition such as is hereinafter described applied either in a liquid state or dry. After removal of the superfluous bronzing material, celluloid varnish and a wax coating such as are hereinafter described, are applied to the cleaned surface.

The metal scrapers or brushes employed are preferably of such a character as to produce a smooth or burnished surface of the metal, and are advantageously driven through a flexible shaft from an electric motor, petrol engine or other convenient source of power.

In a modified form of my invention for use in cases where the corrosion is of such a nature as not to-be readily removable by the means above mentioned, the metal work is treated with an alkaline fluid cleanser such as an aqueous solution of soft soap, American potash (crude potash or pearl Application filed February 27, 1924. Serial No. 695,579.

ash made from wood ashes), and caustic soda, to which quicklime is added.

The alkaline cleanser may be of the following composition, viz, soft soap, 1 lb. to 1 gallon of water; American potash, lb. to the gallon; caustic soda lb. to the gallon; quicklime, 4 oz. to the gallon, if a stronger cleanser is required. I V

This may be advantageously applied with a brush and allowed to remain until the' scale or other coating produced by the corrosion is softened, so as to permit of its removal by means of scrapers, steel wire brushes or like apparatus, which may be operated-either by hand or mechanically, as above mentioned.

Any scale or other product of corrosion which remains after this treatment is removed by applying muriatic acid of sufficient strength, e. g. the commercial acid, for the purpose, the surface being afterwards washed with clean water.

The metal surface is then treated with a weak solution of cyanide of potassium so as to neutralize any acid that may remain in the pores of the metal and at the same time remove any oxide or other coating that may be still present. The action of this solution may be assisted by scouring with pumice powder, pumice stone or the like until the metal surface is perfectly clean. during and after this abrasive process, the surface may be washed with water. When the surface is perfectly clean, in the case where the metal to be treated is bronze, there is sprayed evenly over it a coloring material of the class known as brown bronze composition consisting e. g. of sulphide of ammonia, haematite and powdered graphite, which is in solution or suspension in amyl acetate or other suitable non-oily volatile liquid which will permit of its being sprayed over the metal surface and which will quickly evaporate so as to leave the bronzing powder or composition on the surface. The brown bronze may be of the following composition, viz, haematite, 1 lb;

powdered graphite, 4 oz.; sulphide of ammonia, 2 fluid oz. of a concentrated solution diluted with water in the proportion of one part to six parts of waterfamyl acetate, as required, according to the tone of bronze desired.

After allowing the sprayed bronze to become perfectly dry, the superfluous material is brushed ofi leaving the surface Before or bronzed. In the case of brass, before applying the bronzing composition, the clean metal surface is first treated with a very weak solution of a coloring material of the class known as steel bronze and consisting e. g. of iron filings dissolved in muriatic acid to which white arsenic has been added. This bronze may advantageously have the following composition viz,

1 lb. of iron filings dissolved in muriatic acid, 1 lb. of whlte arsenic, 1 gallon of water. v

The strength of this solution is such that by itself it does not appreciably alter the colour of the metal surface to which it is applied. lVhile this solution which may be applied by means of a swab, is still moist, the brown bronze is applied and afterwards brushed off as above described.

The bronzed surface so produced is then if desired relieved e. g. in the prominent parts, by rubbing the same with pumice powder or other suitable abrasive.

The bronzed surface then receives two, three or more coats of a clear varnish consisting e. g. of celluloid dissolved in acetone and amyl acetate or other suitable solvent, which is preferably applied by spraying under pressure and each coat of which is allowed to dry before the next is applied. With the last coat that is applied, there is preferably added some brown vegetable or other suitable transparent pigment to colour it. By this means the colour of the patina or protective coating produced may be varied as desired.

The varnished surface is finallytoned by applying a liquid coating consisting of beeswax dissolved in turpentine to which vegetable black has been added. This may be brushed very lightly over the varnished surface with a bristle brush, whereupon the surface is polished with a clean leather. The treatment is now complete and the protected surface has a fine appearance and is capable of efiiciently resisting atmospheric influences for long periods of time.

The spraying may be effected by means of a compressed air sprayer of any suitable known construction.

What I claim is 1. A process for treating bronze, brass and like metals, so as to produce thereon a protective coat. the appearance of which can be varied, said process consisting in treating the metal surface with metal abrading devices so as to remove the unsightly products of corrosion and to expose the patinalike surface covering the unacted upon metal, then covering such patinalike surface with a coloring material of the class known as bronze, removing the superfluous part of such coloring material, and then applying celluloid varnish and a wax coating are applied.

2. A process for treating bronze, brass and like metal, so as to produce thereon a protective coat, said process consisting ini applying to the metal surface a mixture of soft soap. American potash, quicklime, an

caustic soda, then acting upon the surface ofthe metal by mechanical abrasion, so as to remove the unsightly products of corrosion and to expose the patinalike surface which covers the unacted upon metal, washing the surface with water, covering the patinalike surface with a coloring material of the class known as bronze, removing the .superfluous coloring material and then applying celluloid varnish and a wax coating.

3. A process for treating bronze, brass and like metals, so as to produce thereon a protective coat, said process consisting in treating the metal surface with metal abrading devices so as to remove the unsightly products of corrosion and to expose the patinalike surface covering the unacted upon metal, then spraying the patinalike surface protective coat, the said process consisting in treating the metal surface with metal abrading devices so as to remove the unsightly products of corrosion and to expose the patinalike surface covering the unacted upon metal, then covering the patinalike surface with a' coloring material of the class known as bronze. removing the superfluous part of such coloring material and then spraying the treated surface with a varnish consisting of celluloid dissolved in acetone and amyl acetate, and then applying a wax coating.

5. A process of treating bronze, brass and like metals, so as to produce thereon a protective coat the appearance of which can be varied, said process consisting in treating the metal surface with metal abrading devices so as to remove the unsightly products of corrosion, and toexpose the patinalike surface covering the unacted upon metal, then covering the patinalike surface with a coloring material of the class known as bronze, removing the superfluous part of such coloring material, and then applying celluloidvarnish and treating the varnished surface with a solution of beeswax in turpentine, in which there is mixed a pigment.

6. A process for treatingbronze, brass and like metals so as to produce thereon a protective coat, said process consisting in applying to the metal surface a mixture of soft soap, American potash, quicklime. and

caustic soda. then acting upon the surface v to remove the unsightly products of corrosion and to expose the patinalike surface covering the unacted upon metal, treating the surface with muriatic acid, washing the surface with water, treating it with a weak solution of cyanideof potassium, applying a coloring material known as bronze, removing the su erfluous part of such coloring material, t en covering the treated surface with celluloid varnish and a wax coatmg.

, 7. A process for treating bronze, brass and the like metals to produce a protective coat thereon, the appearance of which can be varied, said process consisting in abrading the metal surface to remove the unsightly products of corrosion and to expose the patinalike surface covering the unacted ,upon metal, then covering such patinalike surface with a coloring material of the class known as bronze, removing the superfluous part of such coloring material, and then applying celluloid varnish and; a wax coating.

RICHARD WILLIAM main? igox.

Witnesses:

HERBERT A. Bnns'miw, WALTER Bonmson. 

